Best Fertilizers For Asparagus: Ratings, Reviews, and Top Picks
Thinking of planting some asparagus in your vegetable garden for this year's veggie harvest but aren't sure which fertilizer is best? In this review, we compare our favorite fertilizers by analyzing their ingredients, composition, costs, and more.
Asparagus is a unique vegetable because it’s a perennial vegetable. Furthermore, it takes a few seasons to produce shoots that you can safely eat without you needing to worry about killing the plant. That means choosing the right asparagus fertilizer from the start is extremely important.
Most gardeners agree that this vegetable is worth the wait; once you get past the first few years, asparagus can produce tender shoots for over a decade. There are also many different asparagus varieties you can choose from when planting them. Nevertheless, all that waiting can be in vain if your asparagus lacks the nutrients it needs to grow season after season.
For this reason, keeping asparagus fertilized is critical. But if you’re at a loss with where to start, we’ll share our best asparagus fertilizers so that you spend less time researching and more time where you love—in your garden.
At A Glance: Top Asparagus Fertilizers
Dr. Earth Organic
Dr. Earth Premium
Osmocote Smart Release
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Before we talk about our favorite asparagus fertilizers, below are some essential items you should know to help you choose the best-fit fertilizer possible for your situation. Below, we cover in detail, everything you need to know before picking the right fertilizer for your asparagus garden.
Asparagus needs a combination of macro and micronutrients. When looking at most fertilizer labels, they contain three numbers, such as 10 – 10 – 10. These signify the macronutrient content. They stand for the following, respectively:
- Phosphorus (phosphate)
- Potassium (potash)
Micronutrients are also necessary for healthy asparagus plants. Therefore, you should seek a fertilizer that contains nutrients like zinc, boron, and manganese.
Most fertilizers for asparagus come in two forms—granular and liquid.
Granular fertilizer is typically a more economical option since you’ll need to spend time mixing it into the top few inches of your soil. You’ll need to ensure you water the soil well afterward to help the nutrients soak in.
On the other hand, you can add liquid fertilizer to water and spray it over your plants. Fertilizer may also come in a powder form that you dissolve in water. You then apply it the same way you do with liquid.
No two fertilizers are the same. Some provide immediate solutions for droopy-looking asparagus, while other fertilizers have slow-release mechanisms that offer a hands-off approach for months.
Therefore, you should consider the time commitment involved with applying different fertilizers to ensure you find one that matches the amount of time you’re willing to dedicate to it.
Regardless of the fertilizer you choose, it’s crucial to follow the instructions. Even if your asparagus looks sickly from nutrient deficiency, hold yourself back from giving them an extra dose. As the saying goes, too much of a good thing is a bad thing.
Furthermore, if you’re switching between fertilizers, double-check the label. Even if you’re changing fertilizer types within the same brand, they often recommend applying different amounts to ensure that the formula works as intended.
Top Fertilizers for Asparagus
There are many all around vegetable fertilizers that will do just fine with Asparagus. Some of our favorite fertilizers below will also perform well when fertilizing pumpkins or fertilizing peppers. While we prefer a vegetable-specific formula, many can also feed flowers if you choose something that’s a bit more generic with the fertilizer ingredient balance.
Let’s take a look in further detail, and examine our favorite fertilizers for Asparagus, so you can start ensuring your new veggies are well fed.
Miracle-Gro All Purpose Plant Food
- Begins to work instantly.
- Guaranteed bigger growth.
- High nitrogen content.
- Water-soluble formula.
- One gallon covers 10 square feet.
- Doesn’t burn asparagus shoots.
- Safe to use on all plants.
Miracle-Gro is one of the most respected brands in the gardening industry, and their all-purpose fertilizer deserves the top spot on this list. What we love about this product is that it treats asparagus instantly, helping undo signs of malnutrition.
In fact, Miracle-Gro guarantees that you can expect bigger, more beautiful asparagus than if you didn’t apply fertilizer. Because of the instant nature of this product, you can apply it every one to two weeks on an as-needed basis.
To use it, either mix the powder with water or attach a hose to a Miracle-Gro Garden Feeder. In either case, you should spray the fertilizer around the perimeter of, but not directly on the asparagus.
Burpee Bone Meal
- Slowly releases nitrogen.
- Excellent for phosphorus-deficient soil.
- Encourages strong root growth.
- Ideal for planting new asparagus.
- Natural ingredients.
- Doesn’t burn asparagus shoots.
- OMRI listed.
Some soil has plenty of potassium but lacks other essential nutrients. If you know that this is the case in your garden, Burpee’s Bone Meal fertilizer offers an organic way to introduce phosphorus and nitrogen into your soil via its 6 – 8 – 0 makeup.
Furthermore, this product has a high concentration of calcium. As a result, asparagus will grow strong roots for many years of tender shoots. Since bone meal decomposes slowly, you don’t have to worry about it burning your plants.
We recommend using Burpee’s Bone Meal before planting asparagus to maximize results. To do so, mix the dry, granular fertilizer into your soil. Then, water thoroughly to encourage the nutrients to seep into the ground.
Southern Ag All-Purpose Fertilizer
- Equal macronutrient ingredients.
- A little goes a long way.
- Granular formula.
- Ideal for large gardens.
- Contains several micronutrients.
- Suitable for monthly use.
- Custom mixed fertilizer available.
The no-frills Southern Ag is a classic fertilizer suitable for just about any soil type. It offers an equal amount of nitrogen, phosphorus, and potassium, so it’s a great fit if you’re unsure of the soil composition where asparagus grows.
Southern Ag is an excellent option if you have a large crop of asparagus since they offer discounts for bulk orders. Furthermore, they can make a special mixed package for you if you happen to know your soil’s chemical makeup and want a different mix of macro ingredients.
You only need to use one cup of this granular fertilizer per 25 feet of asparagus. It’s safe to apply monthly, and your asparagus will benefit from micronutrients like zinc, sulfur, and manganese.
Dr. Earth Organic Fertilizer
- Feeds asparagus for many months.
- Contains seven strains of microbes.
- Introduces probiotics into the soil.
- Root-healthy ecto and endo mycorrhizae.
- Produces more nutritious asparagus.
- 100% organic.
If the environmentalist in you seeks an organic fertilizer that works effectively as synthetic varieties, look no further than Dr. Earth. The hand-crafted blend contains a TruBiotic mixture with seven strains of soil-friendly microbes.
Furthermore, asparagus will benefit from probiotics and ecto and endo mycorrhizae, which strengthen root growth. Many cheap, synthetic asparagus fertilizers contain chicken manure, sewage sludge, and other ingredients unhealthy for you and your soil. Dr. Earth’s fertilizer doesn’t contain any of these.
You can apply this pet-safe fertilizer when you first plant asparagus, when you transplant them, and as a top dressing on an on-needed basis. Because of TruBiotic’s drought-resistant properties, you’ll find that your asparagus will need less watering.
Miracle-Gro Liquid Plant Food
- Ideal for small asparagus gardens.
- Can reapply every week.
- Fast results.
- Granule-free formula.
- A single bottle lasts a long time.
- Excellent balance of macro and micronutrients.
- Works well with other plants.
If you’re not a fan of granules and powders, Miracle-Gro’s Liquid All-Purpose Plant Food could be one of the best asparagus fertilizers for you. A 32-ounce bottle packs a punch, offering 20 square feet of fertilizer with only four teaspoons of the concentrate.
We recommend using this fertilizer if you have relatively small amounts of asparagus since you’ll need to use a watering can to dissolve the mixture and spread it around your plants. You can reapply this fertilizer as frequently as every two weeks.
As with so many of Miracle-Gro’s products, they guarantee that your asparagus will grow larger and more beautiful than if you didn’t use fertilizer. Furthermore, if you have a little leftover solution in your watering can feel free to use it on your houseplants or other garden vegetables.
Down to Earth Acid Mix Fertilzier
- Reduces alkalinity of the soil.
- Strengthens roots for the winter.
- Promotes growth in the spring.
- All-natural ingredients.
- OMRI listed.
- Safe for monthly application.
- Suitable for new and transplant asparagus.
Asparagus prefers neutral to slightly acidic soil, with an ideal pH range of 6.5 – 7. Therefore, if you have alkaline soil (a pH greater than seven), asparagus likely won’t grow well. Therefore, choosing an acid-based fertilizer like Down to Earth’s acid mix is an excellent choice.
Since asparagus is a perennial vegetable, you can maximize the benefits of this fertilizer by applying it once in the spring and again in the fall. By using it in the spring, you’ll improve your asparagus’ growth. In the fall, this fertilizer treatment will encourage root growth, making your plants more resistant to cold temperatures.
Down to Earth is an all-natural fertilizer. We’re sure you’ll love its ingredient list as much as your asparagus will. It contains items like cottonseed meal, rock phosphate, and fishbone meal.
Osmocote Smart Release Plant Food
- Excellent for perennials.
- Encourages strong roots.
- Lasts four months.
- Gives asparagus an early-season start.
- Equal macronutrient ratio.
- Produces more flavorful asparagus.
- Smart-release technology.
With the words “smart release” in its name, Osmocote offers gardeners a hands-off approach to fertilizing their asparagus. In fact, one application lasts for four months, thanks to their unique granule coating technology.
The way it works is that you mix the large granule balls into the top one to three inches of your asparagus’ soil. From there, you only need to keep asparagus watered. Then, over the next four months, a combination of water and sun on the soil will allow nutrients to seep out from the granule’s semi-permeable resin.
Osmocote promotes its product as being an excellent way to get an early start to the growing season. Therefore, if you can’t wait to grill up your first asparagus of the season, consider putting this fertilizer at the top of your list.
Dr. Earth Premium Gold
- Safe for children and pets.
- Free of synthetics and toxins.
- Enriched with proteins and carbohydrates.
- Multi-mineral formula.
- 100% organic.
- Non-GMO Project Verified.
- Sustainably produced with environmentalist guidance.
If you liked the sound of the Dr. Earth fertilizer we covered earlier but you want to kick it up a notch, their Premium Gold variety is an excellent choice for asparagus. You can expect nothing but the best from Dr. Earth, especially since it’s the only non-GMO verified fertilizer in the United States.
In theory, you could eat this fertilizer since it has human feed-grade ingredients (although we don’t recommend it!). Furthermore, Dr. Earth naturally enriches it with protein, carbohydrates, humic acids, and other trace elements, putting it ahead of many other organic fertilizers on the market.
Finally, asparagus will receive the best of both worlds if you give them Premium Gold—an instant dose of nutrition and slow-release nutrients over several months.
Down to Earth Rock Phosphate
- OMRI listed.
- Natural, mined soft rock.
- Boosts soil’s phosphorus content.
- Lasts several years.
- High calcium and phosphate concentration.
- Low maintenance.
- Increases asparagus production.
If the soil you want to grow asparagus in lacks phosphorus and calcium, treating it with a fertilizer like Down to Earth’s Rock Phosphate is an excellent choice. By using natural mined soft rock phosphate, you’ll organically improve the quality of your soil.
The 18% calcium content in this fertilizer will ensure that your asparagus receives long-term benefits of building phosphate in the soil, which translates into increased phosphorus. That said, since the formula has a macronutrient concentration of 0 – 3 – 0, it’s crucial that your soil already contains sufficient amounts of nitrogen and potassium.
The best way to use Rock Phosphate is by mixing it into the soil before you plant. The natural decaying process that releases calcium and phosphate takes several years, making it great for asparagus’ ideal harvesting age.
Miracle-Gro Shake n’ Feed
- Higher quality asparagus guaranteed.
- Promotes microbe growth.
- Slow-release formula.
- Prevents calcium deficiency.
- Dispersal-friendly jar.
- Encourages root growth.
- Improves water retention.
We’re rounding out this review as we started it—with Miracle-Gro. Their Shake n’ Feed product comes in a “handy” container that allows you to spread the fertilizer around the asparagus with the shake of its handle.
As easy as they make this, the fertilizer has a slow-release formula, so you’ll only need to apply it about every three months. By embracing natural ingredients, the Shake n’ Feed encourages microbes to grow around your asparagus’ roots.
If your soil contains low amounts of calcium, this fertilizer will help replenish it to ideal levels. As a result, your asparagus will form stronger cell walls. In turn, you’ll get to fill your plate with tender, tasty asparagus shoots.
Frequently Asked Questions
Why are my asparagus spears thin?
If asparagus doesn’t have the proper nutrients, its crown won’t have the ability to grow bigger shoots. Furthermore, if you plant asparagus too deep, the sprouts will have difficulty growing up through the soil, thus making them thinner.
Are coffee grounds a good fertilizer for asparagus?
Coffee grounds can help introduce nitrogen into the soil, which is a macronutrient that asparagus needs. Furthermore, if your soil has a pH level above 7, coffee grounds can help bring the pH level down to the 6.5 – 7 range that asparagus prefers. However, take care not to add too many coffee grounds because it could drop the soil’s pH level too low.
When should I harvest my asparagus?
You can expect asparagus to grow faster than usual by using fertilizer. So, it’s important to monitor and cut the shoots when they reach 8 – 10 inches long. Otherwise, the shoots will take on a woody texture that even cooking can’t undo.
Is Epsom salt good for asparagus?
Asparagus is a unique vegetable because it has salt-resistant properties. In fact, you can use salt to prevent weeds around asparagus. Nevertheless, asparagus doesn’t need the minerals in Epsom salt to thrive. Applying too much salt will kill your plant, so it’s better to use traditional fertilizer.
Will fertilizer help my asparagus multiply?
it has the right conditions, including a sunny environment with sufficient water, proper nutrients, and good drainage, asparagus naturally multiplies. Therefore, introducing fertilizer to asparagus will help increase your harvest.
Does fertilizer decrease time to harvest?
No. Even though fertilizer will help your asparagus stay healthy, you should wait three to four years before harvesting it in full. Up until then, it’s safe to pick asparagus sparingly.
What are the most important fertilizer nutrients?
There are three macronutrients that asparagus must have to grow into large, healthy shoots—nitrogen, phosphorus, and potassium. Several other micronutrients and microbes also contribute to healthy asparagus plants.
With all the excellent asparagus fertilizer contenders on this list, we may have left you more confused than before you came here. So, if we had to choose only one, we consider the Miracle-Gro All-Purpose Plant Food to be one of the best asparagus fertilizers because of its instant water-soluble formula.
Furthermore, Miracle-Gro guarantees that you’ll have a more bountiful asparagus yield, and you don’t have to worry about it burning your asparagus shoots. Now there’s only one thing left for you to do—treat your asparagus with fertilizer and await the beautiful asparagus shoots that’ll soon fill your plate.